[galaxy-user] question about sorting barcoded sequences

Hi, I have an Illumina HiSeq lane of sequences, in which I input multiple samples with 5-prime 6 bp barcodes. The barcodes were added in a way so that the barcodes are the first 6 bp in the reads. What I need to do is to sort my reads according to the barcodes, then clip off the barcodes and use the remaining to do mapping. Could anybody advise how I could sort my reads based on the barcodes (e.g. the first 6 base pairs) in Galaxy? Thanks a lot! Tracy